Hydrotreating catalyst of catalytic cracking gasoline

Abstract

A hydrotreating catalyst comprising a Group 8 metal of the periodic table, molybdenum (Mo), phosphorus and sulfur, wherein the average coordination number [N(Mo)] of the molybdenum atoms around the molybdenum atom is from 1.5 to 2.5 and the average coordination number [N(S)] of the sulfur atoms around the molybdenum atom is from 3.5 to 5.0 when MoS2 structure in the catalyst is measured in accordance with extended X-ray absorption fine structure (EXAFS) analysis.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a hydrotreating catalyst containing molybdenum (Mo). Particularly, it relates to a hydrotreating catalyst having high desulfurization activity and desulfurization selectivity when used in hydrotreatment in which a sulfur content in catalytic cracking gasoline is reduced and also hydrogenation of olefins and aromatics is suppressed. [0003] 2. Brief Description of the Background Art [0004] Form the viewpoint of environmental protection of city and roadside air and reduction of environmental burden on a global scale, it has been required to clean exhaust gas from automobiles and reduce the discharge of carbon dioxide. With regard to gasoline-powered automobiles, in order to reduce the discharge of carbon dioxide, it is required to improve fuel economy. Thus, thereafter, it is expected that high mileage automobiles having a direct-injection engine or a lean burn engine may increase. For ...

AI Technical Summary

Benefits of technology

[0011] An object of the present invention is to provide a hydrodesulfurization catalyst for catalytic cracking gasoline having a high degree of MoS2 dispersion in the Group 8 metal of the periodic table-molybdenum-phosphorus-sulfur structure and possessing excellent desulfurization activity and hydrogenation-suppressing function against olefins and aromatics contained.

[0012] The present inventors have found that a hydrodesulfurization catalyst (dried catalyst) for catalytic cracking gasoline obtainable by impregnating a support (carrier) with an impregnating solution for a hydrotreating catalyst for catalytic cracking gasoline, which contains a molybdenum compound, at least one metal compound of Group 8 metal(s) of the periodic table, a phosphorus compound, and a saccharide derivative, drying the impregnated support, and subsequently activating the resulting catalyst by sulfuration with hydrogen sulfide (presulfuration) exhibits a high degree of crystallinity with a high degree of sulfuration and has both of a high desulfurization activity and a suppressive effect on olefin hydrogenation as compared with a hydrodesulfiirization catalyst (burned catalyst) for catalytic cracking gasoline obtainable by impregnating a support with an impregnating solution having the same composition, drying the impregnated support, further heating and burning it, and subsequently subjecting it to the presulfuration. As a result of further analysis on the catalyst structure, they have found that the average coordination number of the molybdenum atoms around the molybdenum atom and the average coordination number of the sulfur atoms around the molybdenum atom remarkably influence the desulfurization activity and the olefin hydrogenation activity, and thus have accomplished the present invention.

Problems solved by technology

Thus, thereafter, it is expected that high mileage automobiles having a direct-injection engine or a lean burn engine may increase.

However, since the nitrogen oxide-reducing catalyst working under oxygen-excessive conditions (lean conditions) is poisoned by sulfur content and cleaning performance lowers, it is still required to achieve further decrease of the sulfur content in gasoline.

However, the apparatus for hydrodesulfurization of these heavy oils is an apparatus requiring a high temperature and a high pressure and hence there exist many technical and economical problems in ultra-deep desulfurization of the staring oils.

However, when the catalytic cracking gasoline is hydrodesulfurized with a conventional desulfurization catalyst, there arises a problem that olefins contained in the catalytic cracking gasoline as components having a high octane number are also hydrogenated to result in decrease of the octane number.

However, there are problems that the suppression of hydrogenation of the olefins is not sufficient, the decrease of the sulfur content is limited since kinds of sulfur compounds capable of being reduced are restricted, and other facilities are necessary since a multi-step and complex process is required.

However, since hydrogenation depth of olefins is also enhanced simultaneously when the desulfurization activity against the catalytic cracking gasoline is tried to be enhanced, there arises a problem that the decrease of the octane number cannot be sufficiently suppressed.

However, since there are no attempt to quantitatively determine the degree of high dispersion of the group 6 metal sulfide and to correlate the degree with desulfurization properties of the catalytic cracking gasoline and reaction properties of olefins, there exists no sufficient guidelines for designing a catalyst for hydrotreatment of the catalytic cracking gasoline and hence it is difficult to respond requests for further improvement of the desulfurization performance and suppressing hydrogenation of olefins.

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